Process for treating rubber and similar materials and products obtained thereby



Patented Nov. 16, 1926.

. 'jjF QZUhIIITE "S A THEODORE wnIT'rELsnY} or RINGOES, NEW JERSEYLANDCHARLES E. naAnLnY,-or

MISHAWAKA, INDIANA. ASSIGNORS TO THE NAUGATUCK CHEMICAL COMPANY, OF

NAUGATUCK, CONNECTICUT, A CORPORATION OF CONNECTICUT.

PROGES FOR TREATING RUBBER AND SIMILAR MATERIALS AND PRODUCTS OBTAINEDTHEREBY.

No Drawing. Original application filed February 19. 1920. Serial No.359.818. .ZDivided and this applica- 'tion filed September 24 Thisinvention relates to processes for treating rubber and similar materialsand to the products obtained thereby, and it IS -moreparticularlyrelated to the process of vulcanizing rubber by a sulphur compound. Aprobable explanation of the use of various *accelerators in thevulcanization of rubber is that they react with the sulphurordinarilyemployed to provide nascent sulphur or an extremely activetype of sulphur which 'in turn must reactwith the rubber to pro- JIv'idevulcanization. There is thus introof this union with the rubber. Inaddition certain accelerators'such as lead oxide lend their colorationto the stock, others impart an undesirable odor to the vulcanizedrubher, and in general the better accelerators introduce considerableadded expense in the vulcanizing process.

One of the objects of the present invention accordingly is to provide avulcanizing agent and a process for 'vulcanizing agent anda process forvulcanization which shall 'j in prove the speed of vulcanization.Another object of the invention is to provide a simple vulcanizingprocess in which the xml'canizing agent shall provide a vulcanizedproduct free from objectionable color, odor,

' etc;

Another object of the invention is to .provide a series of vulcanizedproducts sub- 40 under vulcanizing conditions, with or withstantiallyfree from bloom and having improved ageing properties.

' ,Tlle invention accordingly consists in sub- D is believed to benitrogen sulphide 15 formed.

The material is purified, removing sulphur jecting rubber and similarmaterial to treatment with a vulcanizing agent adapted to transfersulphur from itself to] the rubber out the addition of an accelerator,and vulcanizing therubber. The invention more specifically. comprisesvulcanizing rubber with a substantially halide-free reaction product ofa sulphur halide and an amine.

This application is a division of the copending application Serial No.359,818. filed ebruary 19, 1920, now issued as" 'U. S.

Patent 1,559,393, 0a. 27, 1925.

- carrying out the invention its pre- 1925. Serial No. 58.426.

ferred form, 100 parts of rubber niay ibe ,mixed with 2 parts, of thereaction product of ammonia and sulphur chloride. This reaction product,known as nitrogen sulphide, appears to have the formula N,S

which may be structurally expressed as ass-1 -=-s-nZ The mixture isplaced in a mold and vulcanized under 40 lbs. steam pressure persquare-inch for approximately 10 minutes,

whereupon vulcanization is complete. Ex-

ccssive temperatures and long periods of vulcanization may causeover-vulcanization. The temperature required orthe time, or

- both, may be modified by the inclusion of an accelerator such as. anamine or' an amine derivative.

As an example 100 parts of rubber mixed with 10 parts otzinc oxide, 2parts of nitro gen sulphide and 0.1 part of dimethylammoniumdimethyldith'iocarbamate .may: be vulcanized in a mold at 40 lbs. steampressure for 10 minutes. The sensitiveness of,

the stock to overvulcanization is materially decreased, for the stockmay be allowed to remain in the mold .foras much as 40 minutes or longerif desired Without overvulcanizat-ion. Y

The reaction product of sulphur chloride and ammonia. mentioned above ispreferably prepared as follows:

An excess of gaseous ammonia is run into a 5% (by weight) carbontetrachloride solution of sulphur chloride. Ammonium chloride isprecipitated and the compound, which and ammonium chloride.

The diethyl ester of th'osulphurousacid,

Can;

considered in the general type RS in which either nitrogen or oxygen maybe attached to the sulphur. It is also probable that nitrogen and oxygenmay be replaced by either sulphur or carbon, and other similar elementsor groups. These compounds may be considered as derivatives of thehypothetical acid H0 01 HO S2 related to ps.

They may be prepared by replacing one or both of the chlorines ofsulphur monochloride by various groups. This type of curing agent ischaracterized by the property of regenerating a cold curing agent,probably sulphur monochloride or the like, when treated with gaseoushydrogen chloride in benzol' solvent. In carrying out this test, a smallamount of the curing material is added to a rubber cement in a testtube, and gaseous h -'drogen chloride is led in. solidification of themass indicates vulcanization, and hence that the material being testedis a member of the class herein described.

The reformation of a cold c uring agent from the material is perhaps dueto the assumed double bonded linking of' sulphur S=S. which resemblingas it ddcsthe as sumed linking insulphur chloride is adapted upon comingin contact with gaseous hydrochlorioacid to regenerate thesulphur'chloride, which serves as a cold curing agent.

The vulcanized material made in accordance with the process as indicatedpossesses the variousadvantages of stock'cured in the ordinary mannerwith sulphur as such. It

' will be observed that the speed of cure is product of ammonia and avastly superior to that found when ordinary sulphur is employed. Stocksproduced in accordance with the process herein set forth have excellenthysical qualities, and contain relatively smal amounts of sulphurcombined or otherwise, the combined sulphur being approximately 4 orless. The products have superior ageing properties and tensile strength,and are-free from bloom;

Having thus described our invention; what we claim and desire to"protect by Letters Patent is: a

' 1. A process of treating rubber which comprises subjecting the rubberto the reaction sulphur halide, and vulcanizing the rubber.

"2. A process of treating rubber which comprises subjecting therubber tothe reaction product of ammonia and a sulphur chloride, and vu'lcanizingthe rubber.

general to be comprised under" 3. process of treating rubber whichcomprises subjecting rubber to nitrogen te 'trasulphide, and vulcanizingthe rubber.

4. A. process of treating rubber which comprises subjecting the rubberto the rcaction product of ammonia, a sulphur halide and an organicaccelerator, and vulcanizing the rubber.

5. A process of treating rubber which comprises subjecting the rubber tothe reaction'product of ammonia, a sulphur chloride and an organicaccelerator, and vulcanizing the rubber.

6. A process for-treating rubber which comprises subjecting rubber tonitrogen tetrasulphide and an organic accelerator, and vulcanizing therubber.

7. A process of treating rubber which COIX1 prises subjecting the rubberto the reaction product of. ammonia, a sulphur halide and an amineaccelerator, and vulcanizing the rubber. T

8. A process of treating rubber which comprises subjecting the rubber tothe reaction product of ammonia, a sulphur chloride and an amineaccelerator, and vulcanizing the rubber.

9. A process for treatin rubber which comprises subjecting the ru her tonitrogen tetrasulphide and an amine accelerator, and vulcanizintherubber.

10. Rub er vulcanized with a substantially halide-free reaction productof a sul- Phurhalide andammonia.

11. Rubber vulcanized with a substantially-halide-fre'e reaction productof sulphur chloride and ammonia. I

12. Rubber vulcanized with a nitrogen sulphide. I 4

13. Rubber vulcanized with nitrogen tetra-' sulphide.

' 14. Rubber vulcanized with the reaction product of ammonia and asulphur halide, and an accelerator.

15. Rubber vulcanized with the reaction product of ammonia and sulphurchloride, and an amine accelerator.

16. Rubber vulcanized with the reaction product ofa nitrogen sulphideand an amine accelerator.

Signed at Ringoes, county of Hunterdon,

THEODORE WHITTELSEY. Signed at Mishawaka, county of St.

Joseph, State of Indiana, this 17th day of Sept, 1925. CHARLES E.BRADLEY.

